The cornea, the outer tissue of the eye, is frequently the subject matter of ophthalmic surgery. In a corneal transplant, for example, a central portion of the cornea of a patient's eye is surgically removed. Preferably, the surgical removal is by a cut that is parallel to the axis of the patient's eye. Typically, in the prior art, the surgical removal leaves a hole in the patient's eye that is circularly symmetric about the axis thereof.
The hole is filled by a central portion of a cornea of an eye of a donor. Analogous to the hole, the central portion of the donor's cornea is circularly symmetric about the axis of the donor's cornea. Moreover, when a cut of the donor's cornea is made to provide the control portion thereof, the cut is preferably parallel to the axis of the donor's cornea.
Usually, the cut of the donor's cornea is made by a hollow cylindrical blade that has a cutting edge at one end. The donor's cornea is placed upon a work surface of the fixture and the blade is advanced along its axis towards the donor's cornea.
The desired diameter of the cut of the donor's cornea is usually in the range of six and one-half millimeters to eleven millimeters. And, typically, the desired diameter of the cut of the donor's cornea is in the range of seven to nine millimeters.
The prior art has shown in U.S. Pat. No. 4,236,579, a corneal punch device having a corneal punch and fixture wherein the punch is suitable for use with round blades of various diameters so as to allow for the cutting of various sized donor's cornea.
However, such a corneal punch is not suitable for use wherein it is desirable to maintain the correct rotational orientation of the donor's cornea for transplantation onto a patient's cornea. Further, such a corneal punch is unsuitable for use with blades for cutting non-round or other than round holes in the donor's cornea while maintaining the correct rotational orientation of the donor's cut cornea to the opening or hole cut in the patient's cornea.